SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    96426, 96427, 96428, 96429, 96430, 96431, 
    96432, 96433, 96434, 96435, 96436, 
    96437, 96438, 96439, 96440, 96441, 
    96442, 96443, 96444, 96445, 96446, 
    96447, 96448, 96449, 96450, 96451, 
    96452, 96453, 96454, 96455
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00092

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (96426,96427,96428,96429,96430,96431,96432,96433,96434,96435,96436,96437,96438,96439,96440,96441,96442,96443,96444,96445,96446,96447,96448,96449,96450,96451,96452,96453,96454,96455)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}